Yes, there is a chance of this – but it would only happen to a small country. Many volcanoes are on islands. There a few examples of small islands which are themselves countries, or significant parts of countries, which are so small that even a fairly small eruption would need the country to be evacuated. These could include: Tristan da Cunha or Ascension islands in the Atlantic ocean (each about 100 square kilometres area); and some of islands of the Caribbean volcanic arc.
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